SiC Nanocomposites Research Articles

Fabrication of C-doped SiC nanocomposites with tailoring dielectric properties for the enhanced electromagnetic wave absorption

Microwave absorbing materials with lightweight, strong absorption, broad bandwidth and thin matching thickness have gained considerable attentions in recent years. Herein, C-doped SiC ceramic nanocomposites with heterostructure were successfully fabricated via solvothermal method using renewable glucose as the carbon source. Such nanocomposites show different permittivity dependent on glucose contents. By tailoring the dielectric properties of the nanocomposites, the C-doped SiC nanocomposites using 0.50 mmol/mL glucose solution with a strong reflection loss of −76.6 dB at 16.0 GHz with the thickness of 1.66 mm were obtained. Microwave absorption mechanism indicates that dielectric loss originating from the conductive paths and dipole polarization contributes to the improvement microwave absorption properties. The results provide new strategy for designing and fabricating composites consisting of ceramic and C materials with the strong absorbing and broad bandwidth properties.

Preparation of beaded chains ZrC/C/SiC nanocomposites and their microwave absorption properties

Abstract Designing heating process to obtain beaded chains nanostructures was an effective way to improve electromagnetic wave absorbing properties of SiC. In this work, the beaded chains SiC nanocomposites deposited carbon coating contained homogeneously-distributed ZrC nanoparticles. The dielectric loss of the beaded chains ZrC/C/SiC nanocomposites were investigated in a frequency of 2.0–18.0 GHz, which was increased by about 10 times than the nanowires, reaching 0.41, and the maximum value is 0.66. It was observed that the heterogeneous interface between C, ZrC and SiC, carbon defects and beaded chains nanostructures could effectively enhance the microwave absorption properties of the nanocomposites.

Simultaneous effects of strain rate and temperature on mechanical response of fabricated Mg–SiC nanocomposite

Mg–SiC nanocomposite samples were fabricated using split Hopkinson pressure bar for different SiC volume fractions and under different temperature conditions. The microstructures and mechanical properties of the samples including microhardness and stress–strain curves were captured from quasi-static and dynamic tests carried out using Instron and split Hopkinson pressure bar, respectively. Nanocomposites were produced by hot and high-rate compaction method using split Hopkinson pressure bar. Temperature also significantly affects relative density and can lead to 2.5% increase in density. Adding SiC-reinforcing particles to samples increased their Vickers microhardness from 46 VH to 68 VH (45% increase) depending on the compaction temperature. X-ray diffraction analysis showed that by increasing temperature from 25℃ to 450℃, the Mg crystallite size increases from 37 nm to 72 nm and decreases the lattice strain from 45% to 30%. In quasi-static tests, the ultimate compressive strength for the compaction temperature of 450℃ was improved from 123% for Mg–0 vol.% SiC to 200% for the Mg–10 vol.% SiC samples compared with those of the compaction at room temperature. In dynamic tests, the ultimate strength for Mg–10 vol.% SiC sample compacted at high strain rate increased remarkably by 110% compared with that for Mg–0 vol.% SiC sample compacted at low strain rate.

Effect of SiC particle size on structures and properties of Ni–SiC nanocomposites deposited by magnetic pulse electrodeposition technology

Abstract In this paper, Ni–SiC nanocomposites were deposited on Q235 steel substrates by magnetic pulse electrodeposition (MPED) technique. Microstructures, compositions and microhardness values of obtained composites were determined by scanning electron microscopy (SEM), scanning probe microscopy (SPM), X-ray diffraction (XRD), and triboindenter in-situ nanomechanical testing. Results showed S-30 nanocomposites with fine, compact and uniform structures consisting of fine nickel grains (average size: 381.7 nm) and SiC nanoparticles (average size: 34.2 nm). For SiC particle size of 30 nm, diffraction peaks of Ni and SiC appeared wide with low intensity, indicating S-30 nanocomposites with small sized Ni grains and SiC nanoparticles. Largest TiN content reaching 10.59 wt% was embedded in S-30 nanocomposites prepared at SiC particle size of 30 nm. Final depths of S-30 and S-200 composites were estimated to 15.1 μm and 24.8 μm, respectively. Wear and corrosion properties of Ni–SiC nanocomposites were then investigated. After corrosion testing for 24 h, the weight losses of S-200, S-80 and S-30 composites were recorded as 1.67, 1.44 and 0.95 mg, respectively. Under the same wear experimental conditions, S-200 composite presented the highest mass loss while S-80 composites displayed the lowest mass loss. By comparison, wear mass loss of S-30 nanocomposites was only 37.1 mg.

Production of high performance AA7150-1% SiC nanocomposite by novel fabrication process of ultrasonication assisted stir casting.

The effect of ultrasonic vibration treatment on nanoparticle distribution was successfully investigated and developed a novel fabrication process to produce nano silicon carbide particle reinforced AA7150-1% SiC nanocomposite through a combination of the vortex, double stir casting, and ultrasonic vibration techniques. Ultrasonicfrequency of 20 KHz and with a power capacity of 1000 W was used in the process. Ultrasonic probe was used for proper mixing of the nanoparticles in the molten bath. Microstructure investigation of grain formation, particle distribution, and fracture surface was analyzed through an optical and scanning electron microscope at the as-cast condition. Energy dispersive spectroscopy was used for determining chemical composition of the nanocomposite. In the novel fabrication process, the influence of sonication effect on material properties such as porosity, microhardness, tensile strength were examined and compared with double stir casted nanocomposite material as well as the base material. Mechanical properties of AA7150-1% SiC novel fabrication process were enhanced with a reported increase of 26.05% in tensile strength, and 10.85% in microhardness. 74.1% reduction in porosity as compared to the base alloy. In the double stir casting process, there was 19.6% increase in tensile strength, 2.9% of improvement in microhardness, and 46.96% reduction in porosity as compared to base material properties. The enhancement of material properties with the ultrasonic probe assisted novel fabrication process are attributed to grain refinement of composite and homogeneous distribution of SiC nanoparticles due to the acoustic streaming and cavitation effect.

SiC composite based selective electromagnetic propagation for GHz application

Nano SiC composite has been used intensively in this study to understand its transparency to electromagnetic waves. Different materials have been used as additive fillers in nanoscales to normalize the transmission ability of SiC in a way allows more transparency of electromagnetic. ZnO, Ni, Si, Fe2O3, and Fe3O4 were implemented as additive fillers. Cold pressing method was adopted to fabricate the green samples. A set of samples contained varied filler ranging of 50, 30, 10 percent particle reinforcement. The complex permittivity and permeability were measured using network analyzer by using transmission line theory. The results revealed that the increase in particle filler, especially ZnO increase the transmission of EM. Fe3O4 shows a maximum reflection performance due to the high amount of iron particles. The transmission ability of SiC was controlled by changing the weight fraction of fillers, causing the transparency of SiC to be increased to a maximum value.

On the stability, microstructure, and mechanical property of powder metallurgy Al–SiC nanocomposites during similar and dissimilar laser welding

Aluminum matrix nanocomposites consolidated by powder metallurgy (P/M) have significant potential for practical applications in the aerospace and automotive industries considering their admirable strength to weight ratio and good corrosion resistance. Due to dimensional restrictions in traditional P/M manufacturing routes, similar and dissimilar joining would be essential to design complex structures, however, the stability of Al-matrix nanocomposites during joining process is a crucial issue. In this research, the stability of an Al-6 vol% (50 nm, ex-situ) SiC-2 vol% (15 nm, in situ) Al2O3 hybrid P/M nanocomposite was evaluated during laser joining in comparison to similar and dissimilar joints with commercially pure aluminum (AA1050 alloy). The processing parameters were optimized with a constant focus spot size of 200 μm, laser power of 4 kW, and travel speed of 8 m/min to achieve full-penetration joints. According to the experimental results, the similar P/M nanocomposite exhibited unstable behavior during laser welding due to the formation of porosity associated with clustering and void expansion near SiC nanoparticles. Hence, the fusion zone in both joint designs consisting of similar and dissimilar containing nanocomposite material became heterogeneous due to the presence of clusters and shrinkage micro-voids. The mechanical properties of weldments deteriorated considerably, with large fluctuations in the hardness profiles as well as low joining efficiency (<30%) and brittle fracture. Defects present in dissimilar welds were mainly located at the nanocomposite side.

Optimization of the Process Parameters on the Mechanical and Wear Properties of Al-SiC Nano-Composites Fabricated by Friction Stir Processing Using Desirability Approach

Aluminium silicon carbide (Al-SiC) nano composites find its application in gas turbine exit vane, structural parts of automobile and other structural applications. In the present investigation, optimization of the process parameters on mechanical and wear properties of aluminium SiC nanocomposites fabricated via friction stir processing (FSP) was studied. Three process parameters such as number of passes (A), rotational speed(B) and transverse feed(C) were used. For three factors and three levels, L9 Taguchi method was used to formulate the experimental design. Desirability approach is used to optimize the process parameters in terms of tensile strength, microhardness and wear loss. It is observed that the number of passes is the vital process parameter for tensile strength whereas rotational speed is the vital process parameter for microhardness. For three number of passes, 1500 rpm of rotational speed and 70 mm/min of transverse feed results in optimal process parameter combination for obtaining better values for tensile strength, microhardness and wear loss i.e. A3 B3 C3. The microstructure evaluation for fabricated and worn surfaces was studied using Scanning Electron Microscope (SEM).

Interfacial optimization of SiC nanocomposites reinforced by SiC nanowires with high volume fraction

AbstractHigh volume fraction SiC nanowires‐reinforced SiC composites (SiCNWs/SiC) were prepared by hybrid process of chemical vapor infiltration and polymer impregnation/pyrolysis in this research. SiCNWs networks are first to be made promising a high volume fraction (20 vol%), and the pyrolytic carbon (PyC) interphase with 5 nm is designed on SiCNWs surface to optimize the bonding condition between SiCNWs and SiC matrix. Nanoindentation shows a modulus of 494 ± 14 GPa of SiCNWs/SiC composites without interphase comparing to the one with PyC interphase of 452 ± 13 GPa. However, the 3‐point bending test shows a higher strength of the composite with PyC interphase (273 ± 32 MPa) comparing with the one without interphase (240 ± 38 MPa). The fracture surface is observed under SEM, which shows a longer SiCNWs pullout of the composite with PyC interphase. The energy dissipation during the 3‐point bending test is calculated by the length of nanowire pull‐out, it demonstrates that the SiCNWs with PyC interphase possess better performance for toughening composite. Further characterization proves that the PyC interphase can give SiCNWs/SiC composites higher fracture toughness (4.49 ± 0.44 MPa·m1/2) than the composites without interphase (3.66 ± 0.28 MPa·m1/2).

Thermal Behavior of Spark Plasma Sintered Alumina-Based Nanocomposites

$$\hbox {Al}_{2}\hbox {O}_{3}$$ /SiC and $$\hbox {Al}_{2}\hbox {O}_{3}$$ –CNT nanocomposites have been fabricated by spark plasma sintering (SPS). Thermal properties (e.g., thermal diffusivity, specific heat capacity, and thermal conductivity) of the nanocomposites have been investigated at room temperature and at elevated temperatures for different nanophase contents and SPS temperatures. The field emission scanning electron microscopy with energy-dispersive spectroscopy, and transmission electron microscopy has been used to investigate the microstructure of nanocomposites. The thermal properties of the nanocomposites as well as those of pure alumina were investigated using direct measurement methods. The results showed that a maximum thermal conductivity of 34 W/m K was achieved on alumina after SPS at $$1400\,^{\circ }\hbox {C}$$ , while alumina containing 5 wt% SiC and 1 wt% MWCNTs nanocomposites have maximum thermal conductivities of 24.15 W/m K and 29.62 W/m K, respectively, at a SPS temperature of $$1500\,^{\circ }\hbox {C}$$ . The thermal properties of alumina decrease with the addition of the SiC and MWCNT nanophases, increasing its suitability for electro-discharge machining and fabrication of affordable products with intricate parts. The thermal behaviors of pure alumina and of the nanocomposites at elevated temperatures showed a decrease in the thermal diffusivity and thermal conductivity of alumina–SiC nanocomposites with increasing measurement temperature, while the specific heat capacity increased with increasing measuring temperature. The measurement properties correlated with the microstructure, and various transport phenomena were clearly explained.

Thermal conductivity of Al2O3-SiC nanocomposites prepared by the electroconsolidation method

A comparative study of the thermal conductivity of composite ceramic material samples prepared using electroconsolidation with direct current transmission, was performed in the temperature range of 15–300 K. The experimental data on the temperature dependence of thermal conductivity are approximated within the framework of the Debye phonon spectrum model, taking into account various scattering mechanisms. The optimal consolidation temperature, which ensures the maximum thermal conductivity of the composite, is determined.

ZrC\u2013ZrB2\u2013SiC ceramic nanocomposites derived from a novel single-source precursor with high ceramic yield

For the first time, ZrC–ZrB2–SiC ceramic nanocomposites were successfully prepared by a single-source-precursor route, with allylhydridopolycarbosilane (AHPCS), triethylamine borane (TEAB), and bis(cyclopentadienyl) zirconium dichloride (Cp2ZrCl2) as starting materials. The polymer-to-ceramic transformation and thermal behavior of obtained single-source precursor were characterized by means of Fourier transform infrared spectroscopy (FT-IR) and thermal gravimetric analysis (TGA). The results show that the precursor possesses a high ceramic yield about 85% at 1000 °C. The phase composition and microstructure of formed ZrC–ZrB2–SiC ceramics were investigated by means of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Meanwhile, the weight loss and chemical composition of the resultant ZrC–ZrB2–SiC nanocomposites were investigated after annealing at high temperature up to 1800 °C. High temperature behavior with respect to decomposition as well as crystallization shows a promising high temperature stability of the formed ZrC–ZrB2–SiC nanocomposites.

Development of a gelatin‐g‐poly(acrylic acid‐co‐acrylamide)–montmorillonite superabsorbent hydrogels forin vitrocontrolled release of vitamin B12

ABSTRACTGelatin (Ge)‐g‐poly(acrylic acid‐co‐acrylamide) and montmorillonite (MMT)‐clay‐based nanocomposite hydrogels were fabricated to study the controlled release of vitamin B12. Polymeric hydrogels were characterized with Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). FTIR spectroscopy confirmed the grafting of partially neutralized acrylic acid on a Ge backbone. The incorporation of MMT fillers inside the nanocomposite hydrogels and their increased crystallinity were established by XRD analysis. The rough surface morphologies of the composite hydrogels shown by SEM resulted from the assimilation of MMT inside the same. TEM confirmed the formation of nanosized composites. The average length and width of the MMT platelets were found to be 184.37 and 20.48 nm, respectively. The maximum swelling of the hydrogel was 375 g/g, and the results were established with Design‐Expert software. The biodegradability of the nanocomposite increased in comparison to that of the copolymer hydrogel. Biocompatibility and cytotoxicity studies were also performed. During different time intervals, the controlled release of vitamin B12in artificial gastric fluid (AGF) and artificial intestinal fluid (AIF) was evaluated with a UV–visible spectrophotometer; this resulted in different controlled release curves. The release in AGF was 42%, and in AIF, the cumulative release was 80% over 6 h. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47596.

The Effect of Direct and Pulsed Current in the Presence of Surfactants on the Electrodeposition of Zn–SiC Nanocomposite Coatings

Zn–SiC nanocomposite coatings were electrodeposited from aqueous citrate electrolytes using either direct current deposition (DCD) or pulsed electrodeposition (PED). The effects of various surface-active organic compounds (SDS, gum arabic, gelatin, CTAB, PEG 20000, and Triton X–100) on the coatings’ surface morphology and chemical composition were studied. The influence of pulse frequency and duty cycle on the percentage of the SiC nanoparticles (NPs) incorporated and on the quality of the deposits was also investigated. The amount of SiC NPs incorporated in the Zn matrix was similar for layers obtained by DCD compared to PED. The Zn–SiC coating deposited by PED exhibited a more fine-grained surface morphology. The percentage of SiC co-deposited with Zn was mainly affected by the type of surfactant used. The ionic surfactants (cationic gelatin and CTAB or anionic gum arabic) allowed the co-deposition of considerably higher amounts of SiC NPs with Zn, compared to the non-ionic compounds PEG 20000 and Triton X–100. However, the use of high molecular weight organic compounds such as gelatin and gum arabic led to aggregation of SiC NPs within the Zn matrix.

Methods of combined production of composite powder materials and functional coatings on their basis

A technology for producing powder composite materials consisting of ductile Fe-Cr-Al matrix, a cladding component based on chromium and aluminum nitrides and solid nanosized tungsten carbide composites has been developed. Functional gradient coatings were obtained on basis of the developed powders by microplasma spraying, combining high adhesion and cohesive strength with high hardness of peripheral layers. So coatings based on the developed composite powders are very promising for the protection of parts and components of precision and power engineering from wear under high mechanical stress.

Effect of nano SiC particles on properties and characterization of Magnesium matrix nano composites

Abstract The increasing demand and diverse design requirements with significant weight savings as well as high strength-to-weight ratio as compared to conventional materials have all raised a growing interest towards the field of composites. Ceramic silicon carbide has received wide attention because of its excellent oxidation resistance, corrosion resistance and low density and even at high temperatures. In recent years, Magnesium (Mg) matrix composites have been used in the automotive industry owing to their lightweight property. Mg matrix composites compromise a very high specific strength, excellent castability, good damping capacity and greater machinability. Nanoparticle reinforcements can considerably improve the mechanical properties of the matrix by more successfully stimulating the particle hardening mechanisms than micron-sized particles. The present paper deals with the fabrication and characterization of magnesium matrix reinforced with different wt % (0,0.5 and 1) of nano SiC particles prepared by solidification combined with ultrasonic cavitation process. Mechanical properties such as micro hardness and density and microstructure of the composites were observed. Microstructure of nano SiC composites were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and Energy Dispersive X-ray (EDX). The results showed that the increase in weight % of nano SiC improve the mechanical properties.

Cu2O/hollow mesoporous silica composites for the rapid and efficient removal of methylene blue

ABSTRACT Cu2O/hollow mesoporous silica (HMS) composite was synthesized using HMS as supporting material by the impregnation method. This composite displayed integrated physicochemical performance of Cu2O and HMS, resulting in low density, large surface area and excellent dispersibility. The synthesized nano-sized composite of Cu2O/HMS demonstrated rapid and effective removal for methylene blue with an efficiency of 99.8% with the reaction time of 5 min. Moreover, the Cu2O/HMS composite exhibited high stability and present no obvious performance degradation after seven cycles. The dye removal efficiency stood up to 89% even after 15 cycles. The improved properties of Cu2O/HMS are possibly the account of the collaborative effect between the mesoporous adsorption with Cu2O photocatalysis.

Effects of Thermal Conditions on Microstructure and Mechanical Properties of Cu–SiCp Surface Nanocomposites by Friction Stir Processing Route

In the present investigation, surface-level nanocomposites were prepared by friction stir processing (FSP) using 50 nm-sized SiC particles with a cluster of blind holes as particulate deposition technique on a 6-mm-thick pure Cu plate. Effects of thermal conditions during FSP by three process parameters in three levels using response surface methodology on microstructure and mechanical properties were studied. Regression models were developed for various responses, and ANOVA tool was used to check the adequacy of the developed models. The results showed that the peak temperature achieved during FSP played a vital role in deciding the microstructure of Cu–SiC nanocomposites and the corresponding mechanical properties. FESEM-based microstructural characterizations revealed a uniform dispersion of SiC and its well bonding with the copper matrix. Nanocomposite layers exhibited superior microhardness and dry sliding wear characteristics than the matrix metal. FSP was identified as a low energy consumption route for the successful fabrication of surface-level Cu/SiCp nanocomposites.

Investigating the effect of SPS‎ parameters on densification ‎and fracture toughness of ZrB2-SiC nanocomposite‎

In this study, the effect of sintering parameters on densification and fracture toughness of spark plasma sintering ZrB2-SiC nanocomposites was evaluated. For this purpose, ZrB2-‎‎30 vol% SiC nanocomposites in the conditions of ‎1600 °C-4 min, 1700 °C-4 min, 1800 °C-4 min, 1800 °C-8 min, 1800 °C-12 min‎ were sintered.‎ Scanning Electron Microscopy (SEM) was used in order to investigate the ‎microstructural variations. The bulk density was measured accoring to ASTM C 373–88. Single edge notch beam (SENB) method was used to ‎determine the fracture toughness of samples. Microstructural observations showed that ‎an increase in sintering temperature led to slight ‎increase in SiC grains size but no sensitive variation in ZrB2. However, increasing the sintering time resulted to increase both ZrB2 and SiC grain size. Also, it was found, temperature and time ascent always increases the relative density. In addition, it was concluded that optimal temperature and time to reach the highest fracture toughness are 1800 °C and 8 min, respectively. Investigation of SEM images of the Vickers indent and their path propagation showed that the deviation and branching of crack are the most important toughening ‎mechanisms in ZrB2-SiC nanocomposites.‎

Wear studies on carbon fiber nano SiC composites – a Grey-Taguchi method optimization

In the present study, Taguchi method coupled with Grey is used to optimize the process parameter during wear test on carbon fiber nano-SiC composites. The composites are fabricated with various weight (wt) fraction of nano-SiC particle by hand lay method. The mechanical properties such as tensile and compression strength are studied. The microstructure of fabricated composites indicates a uniform dispersion of nano-SiC particles. The wear test was performed using Taguchi L27 Orthogonal Array (OA). The experiments are conducted using various speed, load, and weight fraction of nano-SiC particle for a constant sliding distance of 1500 m. The optimum process parameter was obtained from the Analysis of variance (ANOVA) and Grey relation grade. The experimental results indicate that the dominant parameter was (wt) fraction of nano-SiC particles followed by speed and load. Confirmation test is also performed to validate the experiments. The results indicate that the multi-responses such as wear loss and coefficient of friction are greatly improved through this approach. Finally, the worn surfaces of the composites are examined through Scanning Electron Microscope (SEM).